Multi-stroke variable displacement engine

Abstract

A vehicle propulsion system and method of operation are presented. As one example, cylinder deactivation and transitioning from four to two strokes is coordinated with transmission shifting to improve vehicle response. Additionally, it is possible to reduce transitions in operating modes to improve drive feel.

The invention claimed is: 
     
       1. A method for a vehicle propulsion system, comprising:
 producing an engine output that propels the vehicle via a transmission by repeatedly performing combustion in a first multi-stroke engine cylinder without performing combustion in a deactivated second variable displacement engine cylinder; and 
 transitioning the first cylinder from a four-stroke cycle to a two-stroke cycle to increase the engine output while up-shifting a transmission gear ratio from a lower gear to a higher gear. 
 
     
     
       2. The method of  claim 1 , further comprising activating the second cylinder and repeatedly performing combustion in the first and second cylinders of the engine to increase engine output; and
 shifting the transmission responsive to activating the second cylinder. 
 
     
     
       3. The method of  claim 1 , further comprising reducing a throttle opening in an intake passage of the first and second cylinders in response to the transition from four-stroke to two-stroke.